1. Field of the Invention
This invention relates to a plug element for an electrical connection, in particular for the electrical connection of switchgear with bus bars or socket elements in distribution boards or units, preferably in withdrawable distribution units.
2. Background Information
Contact systems of the prior art have, perpendicular to the plug or fastening plane, flexible contact tabs or contact segments of a known type, which make contact with the bars carrying the current. Such a contact system is disclosed in German Patent No. 26 47 573, in which a spring tab is folded around a leaf-shaped segment, and is equipped with a coil spring, which is in contact with the inside of the tab and presses it outward, whereby the outer sides of the tab, under pressure from the spring, come into contact with the contact surfaces of two rectangular-shaped bus bars running parallel to them. Such contact systems are relatively sensitive to warping or twisting.
The plug-in contact disclosed in EP 0 086 316 represents another contact system.
This plug-in contact consists of two interacting contact wires which are held in a U-profile by a leaf spring. The contact surface is formed by a center contact tab of the first contact wire and two side contact tabs of the second contact wire, one on either side of the center contact tab. The intended purpose of this complex design is to make the system relatively insensitive to warping or twisting.
German Published Patent Appln. No. 32 43 064 discloses an additional contact system. In this system, plug elements are provided with U-shaped springs, which U-shaped springs counteract the expansion of locator slots located on the plug elements.
These plug elements are provided with sleeves to hold the cable ends. However, they are not suitable for making contact with C-shaped bus bars or bus bars with slot-shaped tap zones.
German Patent No. 31 26 306 also discloses contact units which contain a cage-like housing and several pairs of contact laminars. Each contact laminar is subject to the action of a leaf spring. Such contact units have the same disadvantage as the contact system disclosed in German Published Patent Appln. No. 32 43 064.
The prior art also includes plug systems which have contact laminars. Such contact laminars, as described in the BBC publication "Konstrukteur" 5/69, Page 185, have laminar segments which conform relatively well with the contact surfaces, even if the latter do not run completely parallel.
The individual laminar segments of the louver-like slotted contact strip form an intermediate layer between two contact surfaces. These laminar segments flex around their longitudinal axis with a certain torsional force if they are compressed by these contact surfaces, which means that the contact strip acts as an elastic contact layer.
However, the manufacture of a plug connector to hold the contact laminar strips is complex and expensive.